A variety of acute brain injuries occur in patients presenting to emergency rooms.
These injuries include acute strokes, seizures, head trauma, and sudden changes of consciousness. In 1996, there were 97 million emergency room visits in the United States alone. Of these visits, it is conservatively estimated that at least seven to eight percent, or between 6.8 and 7.8 million people suffered acute brain dysfunction.
Despite these numbers, electroencephalography (EEG), a standard, noninvasive test to evaluate brain function, is not available or rarely performed in emergency departments in the United States. Many emergency departments affiliated with major academic centers never perform emergency room electroencephalography (ER-EEG) on patients with acute brain problems. Few of these institutions even have ER-EEG regularly available, and then only perform 2-3 per month. This presents a serious unmet medical need.
In the last several years, fundamental changes have occurred in the medical community's approach to acute brain injuries and in EEG technology. These changes make provision of ER-EEG critically important to the health care industry.
As an example, acute strokes are now considered medical emergencies. Effective “clot busting” (thrombolytic) therapy, previously used only for heart attacks, is now able to minimize brain damage, but only within a three-hour time window from the onset of the stroke. This time urgency has moved acute stroke from a previously untreatable disorder to a “brain attack,” equivalent in its urgency to heart attack and head trauma. This brain attack paradigm applies to all patients with acute brain injuries, including head trauma, brain hemorrhage, seizures, or acute altered consciousness. The clock for brain survival starts ticking at the onset of the injury and runs out quickly. We now know that rapid and accurate diagnosis and treatment of acute brain injuries determines outcome. Acutely brain-injured patients' survival and quality of survival depend on rapid and accurate diagnosis of their specific brain injuries.
The EEG is known to provide important electrophysiological data about brain function analogous to the electrocardiogram (“EKG”) in acute cardiac injury. The EEG can identify structural, metabolic, seizure, anoxic, and progressive brain abnormalities in the acute setting. This crucial information about brain function in acute brain injuries is currently not obtainable until after patients are admitted to the hospital, which can mean many hours and even days for the brain injury to worsen, often causing irreversible damage by the time it is identified. Further contributing to delay, specialized personnel are needed to administer EEG, and the experts needed to interpret ER-EEGs may be far removed from the emergency department.
The International 10-20 System (“10-20 System”) is a well-known method used to locate scalp electrodes for EEG readings, based on the relationship between the location of an electrode and the underlying area of the cerebral cortex. The 10-20 System teaches the use of a large number of electrodes, requiring either 19 or 21 electrodes, including one electrode position which acts as a ground. Such large number of electrode positions are necessary when taking EEGs for reference against prior standard tests or EECs, but it may not be necessary for specialized needs. For example, U.S. Pat. No. 6,052,619 to John discloses the use of 2 to 16 EEG electrodes in field emergency situations. When using a reduced number of electrodes, however, there is a trade-off between the time saved in placement of the electrodes and the quality of EEG information produced. Fewer electrodes results In longer interApp electrode distances, with greater risk of noise in the reading. It is possible that modification of electrode locations from that taught by the standard 10-20 System, in particular moving the location of the ground electrode closer to one or more active electrodes, might result in improved results. The prior art does not teach modification of electrode locations from that specified by the standard 10-20 System when fewer than the full set of electrodes are used.
Various attempts have been made to construct an apparatus for locating EEG electrodes in emergency situations, but none are adequate to meet the needs of an emergency situation for acute brain injury in which rapid and accurate placement of scalp electrodes Is accomplished by individuals who are in attendance to provide emergency and critical care, but who are otherwise non-expert in setting up and recording EEGs. A head template which makes provision for a reduced number of electrodes, and with indicia designed to be read during emergency application, is needed to meet this need.
Systems that rely upon digital EEG technology and which allow EEG data to be transmitted via a computer network to a single expert EEG reader are known. What is needed is a system that presents a turn-key interface to the non-expert personnel who routinely attend acutely brain-injured victims, preventing change or modification of the electroencephalogram parameters by the field technician, while at the same time allowing extensive control over such parameters by a remote expert EEG reader, who is one of a plurality of readers who are part of a network of trained EEG readers.